A laboratory analysis of dead honeybee samples taken from hives in Clackamas County this summer showed no detection of pesticides, according to the Oregon Department of Agriculture. Officials said that other factors are likely to be responsible for the death of thousands of bees from colonies owned by four local beekeepers.

In addition, Oregon State University examined bee samples from Clackamas County for pests and disease. The analysis found average levels of bee mites and nosema disease, but did not find any evidence that explains the deaths.

ODA’s Pesticides Program and its laboratory in Portland made the testing and analysis of the bees a high priority. ODA developed a screening process that focused on 39 pesticide active ingredients used in Oregon and known to be toxic to pollinators. Creating the customized list of potential suspect pesticides greatly reduced the testing time. Furthermore, the list can be used in future analysis of pollinator deaths. All of the Clackamas County samples tested, each containing hundreds of bees, were negative for any of the pesticides on the list.

ODA is assisting the state’s Joint Task Force on Pollinator Health and continues to work on pollinator issues at the national level. Jeff Stone represents the Oregon Association of Nurseries on this task force, which is expected to report back with recommendations in the fall. The next meetings are scheduled for Aug. 18 and Sept. 29 in Salem. For more information, contact staff liaison Beth Patrino at beth.patrino@state.or.us.